Water heater control



1965 R. D. GRAYSO 3,198,432

WATER HEATER CONTROL Filed Feb. 23, 1962 5 Sheets-Sheet 1 Aug. 3, 1965 R. D. GRAYSO WATER HEATER CONTROL 3 Sheets-Sheet 2 Filed Feb. 23. 1962 prrogvfys Aug. 3, 1965 R. D. GRAYSO 3,193,432

WATER HEATER CONTROL Filed Feb. 25, 1962 3 Sheets-Sheet 5 Z2 INVENTOR.

United States Patent Office,

3,193,432 Patented Aug. 3, 1965 3,398,432 7 WATER HEATER CONTRQL Richard D. Grayson, Arcadia, Calif assignor to International Telephone and felegraph Corporation, Baitinrore, Md, a corporation of Maryland Filed Feb. 23, 1962, Ser. No. 175,144 9 Claims. (Q1. 236-21) The present invention relates to improved constructions of gas controls, particularly useful in controlling the flow of gas to water heaters.

It has long been the aim to provide gas controls for water heaters having the following features: (a) simplicity; (b) inexpensiveness; (c) compactness; (d) convenient and simple assemblage both from the standpoint of initial manufacture and subsequent servicing, using a minimum number of parts that cannot be inadvertently interchanged and result in malfunctioning; (e) safety with respect to gas leakage either under normal gas pressures or abnormally high gas pressures occasioned as, for example, by failure of a gas regulator in a ga line feeding the control.

It is therefore an object of the present invention to achieve these aims.

Briefly, as disclosed herein, these aims are achieved by a new construction which involves a rotary slide valve, instead of a conventional tapered plug valve, as the main control valve, and encapsulating such rotary slide valve in a closed chamber which is formed in part by a removable sealed cover member, the cover member being of special construction with the following features: (a) the cover member mounts the rotary slide valve; (b) the cover member has compartmentized cavities which define in part essential gas chambers; (c) the stationary seat portion of the rotary slide valve is formed flush as, for example, by grinding and lapping process with one sealing face of the cover member and wall members which define, in part, such cavities; (cl) a wall separating two compartmentized cavities is slotted to provide a gas flow passage for the associated pilot burner; and (e) removal of the cover allows convenient access to all parts that may require servicing and these include: the rotary slide valve; a temperature-controlled poppet valve and its actuating mechanism; and a gas filter.

The use of a rotary slide valve in the present construction, instead of a conventional tapered plug valve, obviates many disadvantages found in prior art controls resulting largely from the fact that the stationary seat of the main valve, i.e. rotary slide valve, is now protected in the instant construction and cannot be deformed by an installer or serviceman in application of a fastening tool, such as a wrench, to the control.

Another feature of the present invention involves a new construction of a thermomagnet assembly having the advantages of (1) savings in electric metal; (2) shorter magnetic path; (3) stress-free mounting of the core thereof, eliminating distortion of the core and thereby obviating problems otherwise existing as a result of non-fiat or misaligned poles and decreased permeability; (4) elimination of a mounting hole; (5) elimination of a coil-retention problem; and (6) savings in coil Winding and assembly time.

Another object of the present invention is to provide a construction having the aforementioned features.

A specific object of the present invention is to provide a control of this character involving a two-part die cast casing in which one of such parts forms a cover member and has compartmentized cavities that define in part essential gas chambers of the control.

Another specific object of the present invention is to provide a control using a protected rotary slide valve instead of a conventional tapered plug valve.

Another specific object of the present invention is to provide a gas control construction of this character in which a cover member mounts the main control valve with the seat of such valve being formed flush with a sealing face of the cover member.

Another specific object of the present invention is to provide a gas control construction of this character that comprises a two-part casingwith each of such parts having cooperable compartmentized cavity portions that define essential gas chambers.

Another specific object of the present invention is to provide a gas control construction of this character in which both the manually operated main valve and the temperature-operated valve are urged towards closed position by gas pressure.

Another object ofthe present invention is to provide a control of this character that incorporates also a thermoelectrically operated safety valve which may be manually reset and which may be closed by'that knob which controls the rotary slide valve.

Another object of the present invention is to provide a new simplified construction of temperature-responsive means which is particularly useful in Water heater controls.

Another object of the present invention is to provide a new magnet assembly for thermoelectrically developed currents in a control of this character.

The features of the present invention which are believed to be novel are set forth with particularity in the appended claims. This invention itself, both as to its organization and manner of operation, together with further objects and advantages thereof, may be best understood by referenee to the following description taken in connection with the accompanying drawings in which:

FIGURE 1 is a view in front elevation of a control em bodying the present invention;

FIGURES 2 and 3 illustrate respectively the PILOT and OFF positions of the main valve which is also illustrated in FIGURE 10 in its ON position;

FIGURE 4 is a sectional view taken substantially along lines 44 of FIGURE 1;

FIGURE 5 is a perspective view illustrating a portion of the rotary slide valve;

FIGURE 6 is a sectional view illustrating a portion of the apparatus of FIGURE 10 in section;

FIGURE 7 is a sectional view taken substantially on the lines 77 of FIGURE 10;

FIGURE 8 illustrates a portion of the apparatus shown in FIGURE 10 in a different operating position;

FIGURE 9 is a transverse sectional view taken substantially on the line 99 of FIGURE 1;

FIGURES 10 and 11 are sectional views taken substantially on the lines 1tl1tl and li -11 respectively in FIGURE 9;

FIGURE 12 illustrates constructional features of the safety valve actuator which is also illustrated in FIG- URES 2, 3, 5, 8, 9 and 10;

FIGURE 13 is a sectional view taken substantially on the line 1313 of FIGURE 1;

FIGURE 14 illustrates the control of FIGURE 1 mounted in operating relationship with respect to a hot water tank;

FIGURE 15 is a sectional View, taken like FIGURE 9, illustrating the mountings for the two knobs;

FIGURES 16, 17, and 18 are sectional views taken on corresponding lines 15-16, 1717 and 18-18 in FIG- URE 15;

FIGURES 19 and 20 are perspective views illustrating details of the control knob and temperature knob mountings respectively; and

FIGURE 21 is a perspective view illustrating the inside of the cover member with the rotary slide valve removed.

FIGURE 22 is a sectional view taken substantially on the line 22-22 of FIGURE 6.

Referring to the drawings herein, FIGURE 14 illustrates a typical installation of thecontrol of FIGURE 1 on a domestic hot water storage tank. The control is maintained on the tank 9 by a screw-threaded plug 153 with the tubular temperature-responsive means 1. 12 of the control being immersed in the water within the cylindrical tank 9 and with the control knob 13 and temperature-adjustment knob 14 being located outside of the tank for convenient adjustment.

The tank 9 is encased by heat-insulating material which is retained by an outer sheet metal cover 16. Water is allowed to enter the tank through a cold water inlet pipe 17 and to leave through a hot water outlet pipe 18, the cold water pipe 17 being connected to the water main and the hot water pipe 13 being connected to the various hot Water faucets in a residence. The tank 9 is always filled with water and water flows therefrom only when a user opens a hot water .faucet. It is desired to heat the water in the tank and to maintain the water at a constant preset temperature, and for that purpose there is provided a controlled gas heating system which includes as parts thereof: a main burner 2d, a pilot burner 21 and a thermocouple or pilot generator 22 heated by the pilot burner flame, all conventionally positioned in a conveniently accessible firebox 23 in the form of a chamber below the bottom wall of the tank, the chamber being also heat-insulated by heat-insulating material 24 between a lower cylindrical extension of the tank and the sheet metal cover.

The firebox 23 contains heated products of gas cornbustion which are allowed to escape upwardly through the central flue 25 in the form of a tubular passageway formed in the tank, the lower end of the line being in communication with the firebox 23 and the upper end of the flue being connected to a vent pipe (not shown) which extends through the roof of the residence where the products of combustion and any unburned gases are discharged into the atmosphere outside of the residence.

In order to increase the efiiciency of heat transfer between the combustion products passing through the flue and the water in the tank, there is provided some kind of metal bafiling 27 in the tubular line to produce turbulence of the combustion products as they take a circuitous path in their flow through such fiue.

A source of heating gas under pressure, either natural gas or so-called bottled gas, is connected to the gas supply line 28, and such line is connected to the threaded inlet opening 29, FIGURES 1 and 10, of the control.

The control functions to control the flow of "as to (l) the pilot burner 21, which is in communication with the outlet 52, and also to (2) the main burner 26 through the gas outlet 33, FIGURE 16, the gas being intermixed with air which flows into a venturi section 35 prior to its burning at the main burner 29. The control is also provided with an electric cable 37 and a connection 38, FIGURE 10, which serves to electrically connect the thermocouple 22 to an electromagnet 39 (FIGURE 6) of an electromagnetically and manually controlled valve 452, 41 (FIG-' URE 10) that automatically functions to prevent gas how to both the pilot and main burners whenever the thermocouple 22 is heated insufiiciently, i.e. whenever there is no pilot burner flame for safe ignition of gas.

The control contains three valves, namely the thermoelectric safety valve ill, 41, a temperature-responsive poppet valve 43, 44, FIGURE 9, and a rotary slide valve 47, 48, which are all within the two-part casing 5-9 and effective under various conditions described below to control the flow of gas to the pilot burner 21 and the main burner 28. These various functions are outlined as follows.

Under normal conditions, as illustrated in FIGURE 14, gas is being burned at the pilot burner 21 and the thermocouple 22 is being heated suiliciently by the pilot flame to energize the thermoelectric safety valve and maintain safety valve 49, 41, open. Gas flows in the following ath to the pilot burner: from gas supply line 28 to the threaded inlet opening 29, through safety valve 40, 41, to closed chamber 53, through a grooved portion 55 (FIGURE 7) into filter chamber 57, through filter 58, through passageway 59 and connection 32 to the pilot burner 21. The pilot burner flame is suflicient to properly heat the thermocouple which develops a voltage in response to such heat and such voltage is applied via electric cable 37 to the safety valve coil 39, the coil 39 producing sulficient magnetism to maintain the armature 61 and safety valve element 41 connected thereto by rod 66, in its open position, against the tendency of compression spring 63 which. tends to maintain safety valve 46, 41 closed.

Should the pilot burner flame become extinguished or fail to properly burn for some reason or other, the thermocouple 22 cools and the voltage developed thereby decreases to a point where it is insufficient to maintain the safety valve 40, 41 open, with the result that the safety valve 40, 41 is automatically closed by spring 63 to pre vent gas how to either the pilot burner or main burner. Under this condition a manual resetting of the safety valve is required and is accomplished, as explained hereinafter, using a releasable mechanical connection extending to the circular enlarged portion 65 of armature rod 66 on which is mounted armature .61, spring 63 and valve element 41.

Assuming proper ignition of the fuel at the pilot burner 21, as illustrated in FIGURE 14, gas can escape to the main burner 29 only when the thermostatic poppet valve 43, 44 is opened by the water temperature responsive means 11, 12 and the rotary slide valve element 48 has its port 48A in registry with stationary port 47A. As long as the manual control knob 13 is in a position other than its ON position, no gas can flow to the main burner 29 since the rotary slide valve port 48A is then not in registry with the stationary port 47A. Thus, under these conditions, the control knob is in its ON position, wherein the rotary slide valve port 48A is in registry with the stationary port 47A, as shown in FIGURES 9 and 10, and the thermostastically operated poppet valve 43, 44 then has exclusive control of gas flow to the main burner 28. The poppet valve 43, 44 is automatically opened and closed in accordance with the water temperature which is sensed by the tubular'sensing means 11, 12 such that when the temperature of the water decreases below a preset temperature, the poppet valve 43 44 is automatically opened and closed in accordance with the water temperature which is sensed by the tubular sensing means 11, 12 such that when the temperature of the water decreases below a preset temperature, the poppet valve 4-3, 44 automatically opens to allow gas to how to the main burner 29 and, conversely, when the water temperature increases to such preset temperature, the poppet valve 5,3, 44 automatically closes to prevent further flow of gas to the main burner, i.e. to prevent further heating of the water by the main burner. This mentioned preset temperature is adjusted by manual rotation of the temperature control knob 14 which serves to adjust the position of lever I17 and thereby provide an adjustment of the temperature at which the expansible element 11 is effective to operate the snap disc 72 and cause the poppet valve 4 3, 44 to open. The fiame at the pilot burner 21 is unaffected by the manual setting of the temperature control knob 14 as well as opening and closing of the poppet valve 43, 44 so that at all times there is a pilot flame ready to cause ignition of any gas flowing to the main burner 2%.

When the control knob 13 is either in its OFF position or in its PILOT position (other than in its ON position), automatic opening and closing of the poppet valve 43, 44 in accordance with temperature conditions in the water tank or manual adjustment of the temperature control knob 14 has no effect on the flow of gas to the main burner since the rotary slide valve port 48A is not in registry with port 47A. However, should there be any malfunctioning of the rotary slide valve element 48 in its seat 47 as, for example, by leakage at the seat, the gas is prevented from escaping to the ambient atmosphere due to the closed chamber 53, and such leakage can only be to the main burner 20 where the leaking gas is either ignited by the pilot burner 21 or escapes from the residence through the central flue 25 (FIGURE 14) and vent pipe connected thereto.

Under that condition wherein there is no pilot flame, the safety valve 40, 41 is allowed to close automatically by compression spring 63, thereby preventing the flow of gas to the pilot burner and main burner. A manual resetting operation is then required to place the pilot burner 21 in operation again during which the safety valve 40, 41 is temporarily opened by manual eifort to allow gas to flow to the pilot burner 21 where gas may be ignited by a person while simultaneously using a match to ignite the gas being allowed by manual effort to flow to the pilot burner 21. The manual means for accomplishing this involves a releasable mechanical connection extending from the control knob 13 to the armature extension 65. After a sufiiciently long period of time, say 10 to seconds, during which the gas is manually ignited and the control knob 13 is manually operated to a position slightly beyond its PILOT position, the thermocouple 22 is sufficiently heated by the pilot flame to again suhiciently magnetize the armature 61 and thereby maintain the safety valve in its open position without further manual effort being required on the control knob 13.

Now that the general overall functioning of the control has been outlined, a more detailed description of the control follows.

The control has a two-part casing 59, a first part being referred to as a base member since, as seen in FIGURE 10, the gas inlet and outlet connections and thermocouple connections are made thereto at 2h, 32, 33,

38, respectively, the other part being referred to as a safety valve '40, 41, such valve controlling the flow of gas to both the main burner and pilot burner. Specifically this valve 49, 41 controls the flow of gas to the chamber 53 which is defined in part by' a cavity 82 in the base member 75 and a cooperating cavity 83 (FIGURE 21) in the cover member 76. The main control valve 47, 49 (FIGURE 9), a rotary slide valve, only the stationary seat 47 of which is shown in FIGURE 21, is disposed in the inlet chamber and is mounted exclusively on the cover member 76.

The rotary slide valve 47, 48 has a ground and lapped flat seat 47 which is ground and lapped simultaneously with other inwardly extending protruding portions of the cover member 76 so as to be flush therewith, as illustrated in FIGURE 21. These mentioned other inwardly extending protruding portions of the cover member 76 are various partition or wall members as will be described later. The rotary valve element 48, which sealingly cooperates with its seat 47, is a hat ground plate having a peripheral projection 483. Such plate has a generally arcuate-shaped port 43A, FIGURE 10, therein cooperable with .a like dimensioned port 47A in the stationary flat seat 47 and is loosely mounted on a shaft 85 with such projection 43B extending into a lost motion slot 86, FIGURES 5 and 10, in a generally arcuate-shaped sheet metal plate 87 which is secured to shaft 85 as, for exam- .ple, by riveting, and which has a pair of fingers 87A and 87B extending therefrom for operating the thermoelectric safety valve 40, 41 in a manner described later. The aforementioned lost motion slot 86 is provided in the bent portion 87C of the actuating plate 87 and the aforementioned fingers 87A and 87B also form bent extensions which extend in opposite direction from such bent portion 870. Asmall washer spring 90 is disposed between the valve-actuating plate 87 and the rotary valve element 48 to apply seating pressure between the rotary valve element 48 and its seat 47. Theshaft 85, to which plate 87 is secured, extends sealingly through the boss 91 in cover member 76 and for that purpose there is provided an Oring 92 which is recessed within the shaft and which sealingly engages the wall of the cylindrical boss 91.

The shaft 85 is retained in the boss 91 with the aforementioned spring 90 compressed, as seen in FIGURES 15 and 16, by a spring clip 93, which engages the outer end of the boss 91 and a circular groove in the shaft 85. This clip 93 is removable and has a portion 93A thereof insertable in the cooperating grooved portion 85A in the end of shaft 85 such that the clip and its extension 93B are properly indexed with respect to position of the rotary slide valve element 48. This clip extension 93A is engageable with a cooperating slotted portion 13A in the knob 13 so as to properly index the same with respect to the rotary slide valve element 48 whereby when the knob 13 is rotated with the ON marking thereon in registry with the stationary index mark $95 (FIGURE 1), the valve 47, 48 is fully open as illustrated in FIGURE 9. A screw 96 releasably secures knob 13 on shaft 85. The knob 13 may be rotated in one direction to its OFF position and may be rotated in the opposite direction to its PILOT. position as indicated in FIGURE 1. In both the OFF and PILOT positions the valve 47, 48 is closed as illustrated in FIGURES 3 and 2, respectively. In such movements of valve plate 48, the adjacent ground surface between valve plate 48 and its seat 47 is lubricated with lubricant in and furnished from the lubricant reservoir 98 in the form of a depression in valve seat 47.

Rotation of the knob 13 to its OFF position results in corresponding rotation of actuating plate 87 with its finger 87B engaging the underside of the cylindrical projection .65 on rod 66 and moving it and the valve element 41 carried thereon to its closed position, thereby preventing any gas flow to either the pilot or main burner, the valve element being then retained in its closed position by spring 63. Thereafterthe valve element 41 may be reset to its open position using the technique described above which involves manually rotating the knob 13 to a position slightly beyond its PILOT position and using manual effort for a limited amount of time to hold it in such latter position. In such case the other finger 87A contacts the top side of cylindrical projection 65 and moves the valve element 41 to its open position against the action of coil spring 63, requiring the above-mentioned manual effort during the time the pilot burner is being relit to heat the thermocouple 22; and after the thermocouple is sufficiently heated, the manual control knob 13 may be released. The previously mentioned lost motion slot 86 provides a lost motion connection between the valve plate 48 and the control knob 13 to prevent any closing movement of the valve 41, occasioned as, for example, by thermocouple or pilot flame failure, from effecting movement of such valve plate 48.

It will be seen that when the valve 47, 48 is closed, gas can escape from chamber 53, defined in part by cover cavity 83 (FIGURE 21), only to the pilot via the opening '55 which is in the form of an open-ended notch in the wall 100 of cover 76. This construction is of importance from the standpoint of production costs in that no special conduit or bores are required. I

When the knob 13 is in its ON position, gas may escape through port 47A and one or more openings 101 in wall 101A which lead to the thermostatic control chamber H l! 162, such chamber M2, as shown in FIGURE 21, com prising, in part, the walled cavity 1133 in the cover 76 and containing the coil compression spring 135 which'biases the poppet valve towards its seat 43 for controlling the flow of gas to the bore hole 196 and main outlet 33. The poppet valve 44 tends to be closed by gas pressure in accordance with another feature of the invention. The valve '44 is also controlled by the thermostatic rneans now described in detail.

The poppet valve 44 has its stem slidably mounted in the bore 107 and has an adjustable screw 168 threaded therein for changing its efiective length, such screw being engageable with the conventional snap disc 72 for moving the valve element 44 to open position. The disc 72 has an outer circumferential portion resting on a hardened ring 110 and a more inner circumferential portion engaged by plunger 113 which is loosely slidable in a bore 114 and which has a rounded centrally disposed protuberance lying within a grooved portion near one end of a generally rectangular plate 117, the other end of plate 117 having a rectangular protuberance 121 engaging a temperature-adjusting screw 122 and also with an intermediate portion of such plate 117 having a circular dimpled portion engaged by one end of rod 12. The other end of rod 12 is secured as, for example, by a rolling operation to the closed outer end of tube 11. The inner end of tube 11 is threaded in a closure ring 116 with a sealing O-ring 118 therebetween, the ring 116 being threaded within casing 75 and also having an externally.

threaded portion on which the threaded mounting sleeve 19 is threaded. An epoxy-type cement or other sealing compound 12% is preferably disposed around the inner end of mounting sleeve or fitting 1G and also in the annular region between sleeve and tube 11 to assure a water-tight connection between the hot water tank and control. I

The previously mentioned screw 122, which is threaded in casing half 75, provides an adjustable abutment for bar 117 whereby the temperature may be adjusted at which the snap disc 72 is operated to an overcenter posi- 1.

tion to thereby open valve 43, 44 in accordance with con traction of tube 11. v

This screw 122 sealingly passes through the casing half 75, there being provided an O-ring 125 recessed in such screw for that purpose, and the screw mounts the temperature control knob 14 in the manner now described in connection with FIGURES 15, 17, 18, and 20. i A cap 134 is retained on the outer end of screw 122 by set screw 132 on the cap 13%} engaging an annular grooved portion of screw 122, such set screw 132 being of sufficient length to provide an index for the premarked temperature-adjustment knob 14 which has aligned cooperating bores 14A and MB in flanged portions thereof for receiving the elongated set screw 132. The knob 14 includes also an abutment 14C which cooperates with a protuberance 134 on the cover member 76 to limit rotational movement of the knob 14 and is releasably secured to the assembly by screw 136 threaded in cap 130. It will be seen that the cover 76 may be removed without effecting the adjusted position of the cap 13%) on cover 76, this being so since there is a keyhole-shaped apertured portion 136 (FIGURE 21) in the cover '76 that a lows passage of the cap 139 with the set screw 132 thereon. The knob 14, when in position, obscures vision and access to two cover-securing screws 78 and also to an adjustment for the amount of gas flowing to the main burner.

This later adjustment is in the form of a butterfly valve in passage 196 and specifically is in the form of a disc 140 frictionally held in the slotted end of a small turnable shaft 142 which is frictionally held in a bore in cover '76 by a sealing O-ring 144- recessed in shaft 142.

A similar adjustment for pilot burner flame size is illustrated in FIGURE 13 and involves an adjustable screw 14-4- in casing half 75 with the unthreaded end of the screw being positioned in the pilot gas passageway 59 5 and with the other end of the screw extending into the cylindrical opening 146 in casing half 7 6.

Thus, to gain access to the interior of the control, the temperature-adjustment knob 14 is removed by removing screw 136 and the four cover-fastening screws 78 are loosened or removed. Assembly is accomplished in similar manner with a flat single-piece apertured gasket 148 being sandwiched between confronting surfaces of the casing halves and 76.

For ease in assembly, the poppet valve spring 165, as seen in FIGURE 9, has one of its ends threaded on a grooved extension of shaft 107.

The closure disc 116 is of steel and the epoxy cement 120, besides providing an additional seal, protects the steel disc from rusting. The sleeve 10 is preferably of brass.

The expansible element 11 is of copper and has a higher coefficient of expansion than rod 12.

As alluded to above, the particular construction of the thermo-responsive magnet illustrated in FIGURES 6 and 22 embodies other aspects of the present invention. Such construction involves a short-legged, unapertured, U-shaped core member 150 having practically optically ground aligned pole faces 150A, 1588 and resting on a U-shaped bracket 151 which is inverted with respect to the U-shaped core member. In the preferred form, the coil 39 of insulated wire iswound around both the core and bracket. One end of the coil is'then spot-welded to the insulated terminal 153 and the bracket 151 is secured to the terminal plug 38 by, for example, a staking operation. Then the other end of the coil 39 is spotwelded to the plug 38 which is considered as being at ground potential. drical housing 155 which is formed at its upper end to provide a bearing for the lower end of slidable rod 66 and is crimped or rolled around the plug 38 to secure the same in position. The plug 38 is threaded in the casing half '75 with the upper end of rod 66, as shown in FIGURE 4, extending through a guide bore in the wall 157.

While the particular embodiments of the present invention have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from this invention in its broader aspects and, therefore, the aim. in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of this invention.

1 claim:

1. In a gas water heater control, a generally rectangular casing having two mating parts which define separate gas chambers, one of said two parts having a gas inlet, a thermoelectrically operated safety valve mounted on said one of said parts in communication with said inlet, said two parts having cooperating compartmentized wall portions defining a first one of said chambers, said first chamber being in communication with said inlet through said valve, a flat rotary slide valve in said first chamber and mounted on the other of said two parts, a second oneof said chambers being defined by compartmentized walls of said two parts and being in communication with said first chamber through a grooved'portion in a wall portion on said other part independentiy of said rotary slide valve, gas filter means in said second chamber, a pilot outlet in said one part in communication with said second chamber, a third one of said gas chambers being defined by said compartmentized wall portion of said one and said other parts, a thermostatically operated poppet valve in said third chamber, passageway means between said first and, third chambers, said rotary slide valve controlling the flow of gas in said passageway means between said first chamber and said third chamber, a main burner outlet on said one part in communication with said third chamber through said poppet valve,

said other part comprising a removable cover member which, upon removal, allows access to said first, second The assembly is enclosed by a cylin-' and third chambers, a control knob on said other part operating said rotary slide valve, and means operated by said control knob for operating said safety valve.

2. In a gas Water heater control, a two-part casing, each part having compartmentized Wall portions cooperating with Wall portions of the other part to define a first chamber, a second chamber and a third chamber, one of said parts being a base member having a gas inlet connection, a pilot burner outlet connection and a main burner outlet connection, the other one of said parts being a .removable cover member which, upon removal, allows access to said first, second and third chambers, a rotary fiat slide valve mounted on said cover member within said first chamber, said first chamber being in communication with said inlet, said cover member having a grooved portion in one of its wall portions communicating said first and second chambers independently of said rotary slide valve, gas filter means in said second chamber, said second chamber being in communication with said pilot outlet connection, a thermostatically operated poppet valve on said base member and Within said third chamber, passageway means between said first and third chambers, said rotary slide valve controlling the flow of gas in said passageway means between said first and third chambers, said rotary slide valve comprising a fiat valve seat on said cover member which is ground and lapped flat with the end of said wall portions of said cover member, said rotary slide valve comprising a fiat plate seated on said valve seat, a control knob on said cover member and operatively connected to said plate to control the flow of gas between said first and third chambers, said valveseat having a recess therein for containing lubricant, said recess being closed by said valve plate.

3. In a gas water heater control, a two-part casing, one of said two parts being a base member with a gas inlet connection thereto and a pilot burner connection and a main burner connection thereto, the other of said two parts comprising a cover member, said base member and cover member having aligned cavity portions defined by cooperating wall portions thereof to define a first chamber, a second chamber and a third chamber, said first, second and third chambers being accessible upon removal of said cover member from said base member, said first chamber being in communication with said inlet opening, one of said wall portions of said cover member being grooved to provide a gas flow passage between said first and second chambers independently of said rotary, slide valve, gas filter means in said second chamber, said second chamber being in communication with said pilot outlet connection, passageway means between said first and third chambers, a fiat rotary slide valve on said covermember and within saidfirst chamber and controlling the flow of gas in said passageway means between said first and third chambers, said third chamber incorporating a thermostatically operated poppet valve on said base member, said third chamber being in communication with said outlet connection, and a control knob on said cover member operatively connected to control said rotary slide valve.

4. In a gas water heater control, a two-part casing, one of said two parts being a base member, the other of said two parts being a cover member removably mounted on said base member, said base member and cover member having aligned cavity portions defined by wall portions thereof to define an inlet chamber and a poppet valve chamber, said base member having an inlet connection in communication with said inlet chamber, a flat rotary slide valve mounted on said cover member within said inlet chamber and controlling the flow of gas from said inlet chamber to said poppet valve chamber, said inlet chamber and poppet valve chamber being accessible upon removal of said cover member from said base member, said rotary slide valve comprising a fiat stationary seat on said cover member which is flush with said wall portions defining said cavity portions in said cover member, said cover member having an apertured portion in one of said wall portions communicating said rotary slide valve with said poppet valve chamber, said rotary slide valve comprising a fiat apertured plate on said seat, said seat having a recessed portion therein for containing a lubricant, sid recessed portion being closed by said flat plate,

a knob on said cover member for rotating said plate on its seat, a thermostatically operated poppet valve mounted on said base member in said poppet valve chamber, and an outlet connection on said base member in communication with said poppet valve chamber through said poppet valve.

5. In a gas water heater control, a two-part casing, one of said two parts comprising a base member and the other of said two parts comprising a cover member removably mounted on said base member, said base member and cover member having cooperating cavity portions defined by cooperating aligned wall portions thereof to define an inlet chamber and a poppet valve chamber, said base member having an outlet connection, thermostatically operated valve means on said base member and incorporating valve means controlling the fiow of gas from said poppet valve chamber to said outlet connection, one of said wall portions of said cover member being apertured for the flow of gas to said poppet valve chamber, said cover member having a fiat valve seat thereupon, said fiat valve seat having an apertured portion in communication with said apertured portion in said wall portion, an apertured fiat plate mounted on said seat controlling the flow of gas from said inlet chamber through said apertured portion of said valve seat and through said apertured wall, said valve seat being flush with said Wall portions of said cover member, and means on said cover member for moving said flat valve plate on said seat.

6. In a gas water heater control, a two-part casing, one of said two parts comprising a base member, the other of said two parts comprising a cover member, said base member having a gas inlet connection and a gas outlet connection, said base member and cover member having aligned cavity portions therein defined by inner cooperating aligned wall portions thereof to define a gas inlet chamber, a thermoelectrically operated valve mounted on said base member and controlling the flow of gas from said inlet connection to said inlet chamber, means on said base member normally biasing said valve to closed position, said valve having a movable element extending therefrom into said inlet chamber, a fiat slide valve on said cover member and within said inlet chamber controlling the flow of gas from said inlet chamber to said outlet connection, said slidevvalve comprising a flat valve seat on said cover member, said slide valve comprising a fiat valve plate engaging said valve seat, a shaft extending through said cover member, said valve seat and said valve plate, a valve-actuating member rigidly mounted on said shaft within said inlet chamber, said valve plate being loosely mounted on said shaft between said actuating member and said valve seat, a lost motion connection be tween said actuating member and said valve plate, said actuating member having a finger thereon engageable with said valve element to move it and operate said thermoelectrically operated valve.

7. In a gas water heater control, a two-part casing, one of said parts comprising a base member, the other of said parts comprising a cover member joined to said base member in a common plane, a flat poppet valve seat on said base member and flush within said plane, a poppet valve element slidably mounted in said base member and cooperating with said seat, a spring between said poppet valve element and said cover member, a snap-acting disc on said base member and engageable with said poppet valve to move the same against the action of said spring, means for actuating said snap-acting disc, said means com prising a tube, a rod within said tube, said rod and tube having different coefiicients of expansion, a bushing member threaded in said base member, said tube being threaded in said bushing member, said rod being slidably mounttoad ed in and through said bushing member for actuation of said snap-acting disc, and a sleeve member threaded on said bushing member, said sleeve member being coaxial with said tube and said rod and serving to secure said control on a hot water tank with the rod and tube extending into said tank. 7

8. A control as set forth in claim 7 wherein said base member has an outlet connection and a conduit extending from said outlet connection to said valve seat, adjustable means on said base member for adjusting the flow of gas through said conduit, temperature-adjustment means mounted on said base member for adjusting the temperature at which said rod produces actuation of said snapacting disc, said temperature control means including a rotatable shaft extending through said cover member, a knob on said shaft, said knob being positioned to block access to said flow-adjusting means.

9. A control as set forth in claim 8 wherein said shaft has a cap releasably secured on said shaft, an elongated set screw securing said cap on said shaft, said knob having a grooved portion for receiving said set screw, means securing said knob on said cap, said cover member having an elongated slot to allow said set screw to move therethrough upon removal of the cover member from the base member, said elongated slot allowing access to said flow-control means when said knob is removed from said cap.

References Cited by the Examiner UNITED STATES PATENTS 1,317,951 10/19 Backstrom 236-102 1,762,188 6/30 Morrow 236-102 2,061,716 11/36 Pratt et a1. 251-180 X 2,166,875 7/39 Overbeke 251-180 X 2,302,407 11/42 Waddell 236-99 2,438,447 3/48 Maynard 236-48 2,540,056 1/51 Robinson 251-180 X 2,732,848 1/56 Guelson 137-66 2,766,773 10/56 Grayson 236-21 X 2,822,133 2/58 Grayson et a1. 236-21 2,832,364 4/58 Matthews 137-66 2,880,936 4/59 Jackson et a1. 236-21 "2,925,221 2/60 Currie 236-21 X 2,953,937 9/60 Jackson et al. 236-21 X 2,968,309 1/61 Coffey 137-66 3,063,639 11/62 Grayson et al 236-21 FOREIGN PATENTS 835,969 5/60 England. 507,582 9/ 30 Germany.

- EDWARD J. MICHAEL, Primary Examiner.

ALDEN D. ST EV/ART, Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 3,198 ,432 August 3 196! Richard D. Grayson It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

In the heading to the drawings, Sheets 1, 2 and 3, for "R. D. GRAXSO." read R. D. GRAYSON (SEAL) Attest:

EDWARD J. BRENNER Commissioner of Patents ERNEST W. SWIDER Attesting Officer 

5. IN A GAS WATER HEATER CONTROL, A TWO-PART CASING, ONE OF SAID TWO PARTS COMPRISING A BASE MEMBER AND THE OTHER OF SAID TWO PARTS COMPRISING A COVER MEMBER REMOVABLY MOUNTED ON SAID BASE MEMBER, SAID BASE MEMBER AND COVER MEMBER HAVING COOPERATING CAVITY PORTIONS DEFINED BY COOPERATING ALIGNED WALL PORTIONS THEREOF TO DEFINE AN INLET CHAMBER AND A POPPET VALVE CHAMBER, SAID BASE MEMBER HAVING AN OUTLET CONNECTION, THERMOSTATICALLY OPERATED VALVE MEANS ON SAID BASE MEMBER AND INCORPORATING VALVE MEANS CONTROLLING THE FLOW OF GAS FROM SAID POPPET VALVE CHAMBER TO SAID OUTLET CONNECTION, ONE OF SAID WALL PORTIONS OF SAID COVER MEMBER BEING APERTURED FOR THE FLOW OF GAS TO SAID POPPET VALVE CHAMBER, SAID COVER MEMBER HAVING A FLAT VALVE SEAT THEREUPON, SAID COVER SEAT HAVING AN APERTURED PORTION IN COMMUNICATION WITH SAID APERTURED PORTION IN SAID WALL PORTION, AN APERTURED FLAT PLATE MOUNTED ON SAID SEAT CONTROLLING THE FLOW OF GAS FROM SAID INLET CHAMBER THROUGH SAID APERTURED PORTION OF SAID VALVE SEAT AND THROUGH SAID APERTURED WALL, SAID VALVE SEAT BEING FLUSH WITH SAID WALL PORTIONS OF COVER MEMBER, AND MEANS ON SAID COVER MEMBER FOR MOVING SAID FLAT VALVE PLATE ON SAID SEAT. 